Hydroalkylation catalyst and process

ABSTRACT

A method for the catalytic hydroalkylation of an aromatic hydrocarbon. An aromatic hydrocarbon, for example, benzene is contacted with hydrogen and a dual function catalyst at hydroalkylation conditions including a temperature within the range of about 110* to 450* F. and at a hydrogen pressure of at least one atmosphere. The dual function catalyst comprises a Group VIII metal or metal compound selected from the group consisting of nickel, cobalt and palladium and an acidic oxide suppport consisting essentially of a substantially alkali metalfree mixture of about 5 to 60 percent by weight of a crystalline zeolite and about 95 to 40 percent by weight of a silica-alumina cracking catalyst. Preferred Group VIII metals include nickel and palladium. The hydrogenation activity of the Group VIII metal may be modified by the inclusion of tungsten. Before use the composite catalyst is calcined at a temperature within the range of about 800* to 1,500* F. and is reduced with hydrogen at a temperature within the range of about 400* to 1,200*F. The process is useful in the hydroalkylation of benzene to prepare cyclohexylbenzene.

United States Patent 1 91 Arkell et al.

11] 3,760,017 1451 Sept. 18, 1973 HYDROALKYLATION CATALYST AND PROCESS [75] Inventors: Alfred Arkell, Wappingers Falls;

John M. Crone, Jr.', Fishkill; Robert M. Suggitt, Wappingers Falls, all of NY.

[73] Assignee: Texaco, Inc., New York, NY.

[22] Filed: May 17, 1971 21 App]. No.: 144,211

[52] U.S. Cl. 260/668 F, 260/667, 260/668 R [51] Int. Cl. C07c 15/20 [58] Field of Search 260/667, 668 R, 668 F [56] 1 References Cited UNITED STATES PATENTS 3,412,165 11/1968 Slaugh et al. 260/667 3,153,678 10/1964 Logemann 260/667 3,274,276 9/1966 Louvar 260/667 3,317,611 5/1967 Louvar et al. 260/667 3,397,249 8/1968 Aben et al. 260/667 3,491,019 1/1970 Pollitzer et al 260/667 Primary Examiner-Curtis R. David Attorney-Thomas H. Whaley, Carl G. Ries and H. L. Madinger [57] ABSTRACT A method for the catalytic hydroalkylation of an aromatic hydrocarbon. An aromatic hydrocarbon, for example, benzene is contacted with hydrogen and a dual function catalyst at hydroalkylation conditions including a temperature within the range of about 110 to 450F. and at a hydrogen pressure of at least one atmosphere. The dual function catalyst comprises a Group V111 metal or metal compound selected from the group consisting of nickel, cobalt and palladium and an acidic oxide suppport consisting essentially of a substantially alkali metal-free mixture of about 5 to 60 percent by weight of a crystalline zeolite and about 95 to 40 percent by weight of-a silica-alumina cracking catalyst. Preferred Group Vlll metals include nickel and palladium. The hydrogenation activity of the Group Vlll' metal may be modified by the inclusion of tungsten. Before use the composite catalyst is calcined at a temperature within the range of about 800 to 1,500F. and is reduced with hydrogen at a temperature within the.

range of about 400 to 1,200F. The process is useful in the hydroalkylation of benzene to prepare cyclohexylbenzene.

14 Claims, No Drawings 1 HYDROALKYLATION CATALYST AND PROCESS BACKGROUND OF THE INVENTION Cycloalkylbenzenes may be produced by the hydroalkylation of benzene and alkylbenzene hydrocarbons. For example, benzene may be reacted with hydrogen in the presence of a hydroalkylation catalyst to produce cyclohexylbenzene. By-products of this reaction may include cyclohexane, methylcyclopentane, dicyclohexylbenzenes and polycyclohexylbenzenes. Similarly, toluene may be hydroalkylated to produce methylcyclohexyltoluenes. Other alkylbenzenes may be hydroalkylated to produce the corresponding alkylcyclohexylalkylbenzenes. Mixtures of dissimilar aromatic hydrocarbons may be hydroalkylated in which case the more readily hydrogenated species tends to alkylate the less readily hydrogenated compound. For example, a hydroalkylation of a benzenetoluene mixture may produce a product predominating in cyclohexyltoluene since benzene may be hydrogenated more readily than toluene. Products of the hydroalkylation process such as cyclohexylbenzene are valuable as solvents and as chemical intermediates. For example, cyclohexylbenzene is of commercial importance as a solvent and plasticizer in the plastics coatings and adhesive fields and as an intermediate in the manufacture of cyclohexanone and phenol by air oxidation and acid decomposition.

It is an object of the present invention to provide an improved catalyst and process for the hydroalkylation of benzene and alkylbenzene hydrocarbons. It is a further objective to provide a highly active hydroalkylation catalyst achieving high selectivity in conversion of benzene and alkylbenzenes to the corresponding cyclohexylbenzenes and cyclohexylalkylbenzenes. It is a further objective to provide a stable hydroalkylation catalyst capable of maintaining a high activity and selectivity in sustained use on a continuous basis.

SUMMARY OF THE INVENTION It is postulated that the hydroalkylation of benzene to cyclohexylbenzene, as an example of the hydroalkylation process, proceeds by hydrogenation of a part of the benzene to a cyclohexene intermediate which intermediate then alkylates remaining benzene to produce the cyclohexylbenzene product. Thus the dual catalytic functions of hydrogenation and alkylation are required. However, a careful balance of these two functions is necessary such that the hydrogenation and alkylation reactions may proceed at complimentary rates. Hydrogenation activity is imparted by the use of a metallic catalyst, for example, a Group VIII metal while alkyl ation requires an acidic type catalyst. Excessive hydrogenation activity results in the production of unwanted cyclohexane whereas excessive acid activity may result in isomerization of the intermediates so that the final reaction product comprises a variety of products besition is calcined at a temperature within the range of about 800 to -l500F. preferably within the range of about l00O to l200F. and is reduced at a temperature within the range of about 400 to l200F. and preferably within the range of about 500 to lOO0F. to prepare the hydroalkylation catalyst of our improved process. I-Iydroalkylation is effected by contacting an aromatic hydrocarbon charge selected from the group consisting of benzene, alkylbenzenes, and their mixtures with the foregoing catalyst at hydroalkylation conditions including a reaction temperature within the range of about 1 10 to 450F. and preferably within the range of about 300 to 400F. and at a hydrogen partial pressure in excess of one atmosphere and preferably within the range of about 100 to 500 pounds per square inch gauge.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The improved process of the present invention is carried out in the presence of a novel hydroalkylation catalyst. The catalyst comprises a hydrogenating component and an alkylating component. The hydrogenating component comprises a metal or a compound of a metal selected from the grop consisting of cobalt, nickel and palladium which are Group VIII metals. The alkylating component of the catalyst comprises an acidic oxide support consisting essentially of a substantially alkali metal-free mixture of about 5 to 60 percent by weight of a crystalline zeolite and about 95 to 40 percent by weight of a silica-alumina cracking catalyst. The hydrogenating component may be modified by the inclusion of tungsten or a tungsten compound.

The crystalline zeolite used in the catalyst is advantageously prepared from Zeolite Y, described in US. Pat. No. 3,130,007, because catalysts prepared therefrom have high steam and thermal stability. The crystalline zeolite is modified to the extent that a considerable portion of the alkali metal is substituted by a hydrogen ion or an ion which is convertible to hydrogen, for example, ammonium. Sodium, present in the zeolite as originally produced-is replaced by the positive hydrogen or ammonium ion by means of ion exchange. Suitably, this is done by contacting the zeolite with an aqueous solution of an organic or ionorganic acid or an ammonium compound. Suitable acids include hydrochloric acid, sulfuric acid, nitric acid, sulfurous acid, acetic acid, oxalic acid, propionic acid, benzoic acid and the like. Ammonium ion may be supplied from nitrogen-containing compounds such as ammonium chloride, ammonium sulfate, ammonium sulfide, methylamines and the like.

For the removal of more than about percent of the metal, for example, sodium ion from the zeolite, it is desirable to employ ammonium ion exchange rather than acid treatment since zeolites tend to decompose in a medium having a pH below about 2.5 to 4. The ammonium exchange zeolite is calcined to drive off ammonia and obtain the zeolite in the hydrogen form. The crystalline zeolite is composited with a silica-alumina cracking catalyst in an amount of about 5 to 60 percent by weight of the composite. The silica-alumina cracking catalyst may comprise about .5 to 30 percent by weight alumina and the balance silica.

The silica-alumina cracking catalyst constituent of our composite catalyst may be any of the well known and commercially available silica-alumina cracking catalysts including both synthetic catalysts and those prepared by the processing of clays. Such catalysts are described for example in US. Pat. Nos. 2,363,231, 2,469,314 and 2,935,463.

ica, 25% alumina cracking catalyst filtercake containing 7.9% solids. The mixture is filtered, dried overnight at 300F. and then calcined at 1,000F. with a loss of ignition of 11.2% to produce an acidic oxide catalyst Ordinarily the hydrogenating component is added to support. the composite of crystalline zeolite and silica-alumina A 585 gram portion of the acidic oxide support is comprising the acidic oxide support. Preferably this is sieved through a 20 mesh screen and then mixed with done by contacting the composite with a solution of a a solution containing 238 grams nickel nitrate and 217 compound of the hydrogenating metal component. The grams ammonium metatungstate in 350 ml water. The hydrogenating component may be deposited by drainmixture is dried on a steam plate and after the addition ing any excess solution from the composite and drying. of 5% sterotex (a hydrogenated vegetable oil) is pilled, Ordinarily the catalyst is then calcined in an oxidizing the resulting catalyst is dried with air at 700F. or 4 atmosphere. By this procedure the hydrogenating comhours, calcined at 1,000F. for 4 hours and then reponent will be in the form of the oxide deposited on the duced, by contact with hydrogen for 4 hours at 900F. acidic oxide support. Hydrogenating component may The resulting catalyst is evaluated for hydroalkylation also be incorporated into the composite by ion exof benzene at the conditions and with results shown in change using a solution of a salt of a metal of the hydro- Table I. genating component. The hydrogenating component may also be incorporated directly into the crystalline TABLE I zeolite prior to compositing by ion exchange of the al- E xample 1 2 kall metal form of the zeolite with a soluble salt, for ex- Temperature "F, 300 300 ample, the chloride of the hydrogenating metal. The Pressure P' s- 425 450 h d t. t th f b It Benzene Feed rate, gms/hr. 179 177 y rog'ena mg componen m 6 case 0 co a or Hydrogen Feed rate mols/hr. 0.42 0.74 nickel is generally present in an amount between about g id H ur y mg z o y 2 2 t 1. 3 and 50 percent by weight of the total catalyst comg gg f 821 721 posite and preferably within the range of about 5 to 35 Methylcyclopentane (MCP) 0.1 0.2 Cyclohexane (CH) 1.8 2.8 percent. When employing palladium as the hydrogenat Cyclohexylbenzenes (CH8) 14.0 2' '5 ing component, 11: 18 present in an amount wlthln the Dicyc|hexy1benzene5(DC|-|B) L9 3 range of about 0.05 to 5.0 and preferably within the S Hnidentifiedu d 9 range of about 0.1 to 2.0 percent by weight of the cataelecumy (CHE/a pm um) lyst composite.

c 4 1 t In an example of the preparation of the ac1d1c oxide A atalyst comPrdsmg pe.rcem cobal pared by compositmg the acidic oxide support used in support a commercial Zeohte Y purchased from the Example I with cobalt nitrate, extruding, calcining and Lmde Division of Union Carbide Corporation is base reducing. This cobalt catalyst is evaluated at the condiexchanged to remove alkali metal and then mcorpotrons and with the results shown in Table 11. rated in a silica-alumina cracking catalyst. A 16,000 gram portion of the sodium Zeolite Y is slurried in a 50- TABLE n lution containing 12,000 grams ammonium sulfate and 60 liters of water for two hours at 200F. and then 111- Example 3 4 tered. This ion exchange procedure is repeated twice gfx g z 23g 238 with fresh ammonium sulfate solutions and the resulta' mS/M 86 85 ing zeolite washed free of sulfate ion and then dried at gigs?" Feed mols/hh 300F. A 3,492 gram portion of this partially decation- Product Analysis wt. ized zeolite is calcined at 1,000F. for three hours with 4 Benzene 73.6 32.7 a product recovery of 3,318 grams. The calcined zeo- 5 2 lite is then further ion exchanged with a solution con- CHB 13.3 9.6 taining 6,000 grams of ammonium sulfate in 120 liters DCHB. o Impurities 0.8 0.6 of water for two hours at 200 F. and then filtered. This Seiecivily (CHE/a" pmducm 52 55 procedure is repeated once and the filter cake washed free of sulfate, dried and then calcined at 1,500F. for A series of catalysts are prepared by the foregoing three hours. The p od ct analy i 15 (123% 2 procedures employing nickel as the Group VIII metal 16.5% A1,O 63.7% SiO and it has a Surface area of wherein the nickel content of the composite and the 608 m /g. crystalline zeolite content of the acidic oxide support A 400 gram portion of the calcined decationized zeoare varied. These catalysts are tested at the conditions lite is thoroughly mixed with 15,180 grams of Slland with the results shown in Table "I,

7 I TABLE 111 Example 5 6 7 8 9 10 11 12 13 N kel, wt. nt of t 1 t 6 6 03518111113 xii lil c, wt ge chht of acidic 6 6 4 4 4 4 4 oxide support 12 i2 22 22 22 22 22 22 22 Temperature F- 325 380 250 300 375 420 330 350 400 Pressure, p.s.1.g 5 500 431 400 510 510 480 465 404 Benzene feed, ccJhr 201.25 201. 25 202.5 215 202. 5 205 202.5 205.0 207.5 Hydrogen feed, s.c.f./hr 1.35 1.35 .220 1. 0s 1. 45 1.4 1.3 1.3 1.15 LHSV 2 2 2 2 2 2 2 2 .5 .3 .3 1.3 10.17 13.8 1%. 3.3 10. 12.1 11.1 20.9 20.9 Unidentified- 2.3 0.3 0.3 1.1 1i

In accordance with the process of this invention, we have found that the selection of calcining and reducing conditions is important in achieving high yields and high selectivity in the hydroalkylation reaction. The afture than the catalyst containing a lower percentage of zeolite. Example 28-illustrates the marked effect of the hydrogenating metal employed on the reducing temperatures selected. In this case, a catalyst comprising 6 fect of these variables is shown in the following exam- 5 percent nickel on an acidic oxide base containing 8 ples 14 to 28. In each case, the indicated catalyst is first percent zeolite gives a productivity of 279 when c l. calcined and then reduced at the tabulated conditions. cined at 1,000F. and reduced at 900F. In all examples, 39 grams (0.5 mole) of benzene and We claim: 2.25 grams of catalyst are added to the reactor. The re-- 1. A method for the catalytic hydroalkylation of an actor is then purged with hydrogen, heated to a reacaromatic hydrocarbon charge selected from the group tion temperature within the range of 370 to 380F. and consisting of benzene, alkylbenzenes and their mixtures pressured with hydrogen to a pressure of 500 p.s.i.g. which comprises contacting said aromatic hydrocarbon Reaction is continued by rocking the reactor while charge and hydrogen at hydroalkylation conditions maintaining the pressure at 500 p.s.i.g by the continuwith a calcined and reduced catalyst comprising a ous addition of hydrogen until 4,650 cubic centimeters 15 Group Vlll metal selected from the group consisting of of hydrogen are absorbed. Conversion is expressed as cobalt, nickel and palladium and an acidic oxide supthe ratio of the weight of benzene converted to the port consisting essentially of a substantially alkali metweight of benzene charged X 100. Selectivity is exal-free mixture of about 5 to 60 percent by weight of pressed as the ratio of the weight of cyclohexylbenzene a crystalline zeolite and about 95 to 40 percent by in the product to the weight of benzene converted X weight of a silica-alumina cracking catalyst. 100. Productivity is expressed as the ratio of the weight 2. The method of claim 1 wherein said hydroalkylaof cyclohexylbenzene to the product of the time in tion conditions include a reaction temperature within hours and the catalyst volume. The catalyst composithe range of about 110 to 450F. and a hydrogen partions, calcining and reducing conditions, and the hytial pressure of at least one atmosphere. droalkylation results with each are shown in Table IV. 3. The method of claim 1 wherein said hydroalkyla- TABLE IV Catalyst Product Percent Percent hydrozeolite Calcinlng Reduction Conver- Selecgenating in acidic slon, wt. tivity, Producmetal oxide base Hrs. Tengpfi, Hrs. T8191? MCP CH CHB DCHB percent percent tivity percent palladium on an acidic oxide base containing 7 8 percent zeolite. Within the series calcined at l,00 0F., productivities increase as the reducing temperature is decreased and a maximum productivity of 211 is obtained using the catalyst reduced at 500F. Within the series calcined at 1,200F. a similar dependence on reducing temperature is found, productivities increasing from 98 to 224 for catalysts reduced at temperatures ranging from 800F. to 500F. respectively.- A further increase in productivity to 259 is obtained with a catalyst comprising 0.75 weight percent palladium on an acidic oxide support containing 30 weight percent zeolite, calcined at l200F. and reduced at 500F. as shown in Example 25. Examples 23 to 27 indicate that the catalyst containing the higher percentage of zeolites are more sensitive to reducing temperai133 conditionsinclude a reaction temperature within the range of about 300 to 400F. and a hydrogen partial pressure within the range of about to 500 pounds per square inch gauge.

4. The method of claim 1 wherein said Group Vlll metal is nickel.

5. The method of claim 1 wherein said Group Vlll metal is palladium.

6. The method of claim 1 wherein said catalyst consists essentially of tungsten, said Group VIII metal and said acidic oxide support.

7. A method of claim 1 wherein said crystalline zeolite isprepared by an alternative sequence of at least two ion exchanges and two calcinations.

8. The method of claim 1 wherein said catalyst is calcined at a temperature within the range of about 800 to l500F.

9. The method of claim 1 wherein said catalyst is calcined at a temperature within the range of about 100 0 to l200F.

10. The method of claim 1 wherein said catalyst is re duced at a temperature within the range of about 400 to 1200F.

11. The method of claim 1 wherein said catalyst is reduced at a temperature within the range of about 500 to lOF.

12. The method of claim 1 wherein said aromatic hydrocarbon charge is benzene.

13. The method for the catalytic hydroalkylation of benzene which comprises contacting said benzene charge and hydrogen at hydroalkylating conditions with a calcined and reduced catalyst comprising nickel and an acidic oxide support consisting essentially of a substantially alkali metal-free mixture of about 5 to 60 percent by weight of a crystalline zeolite and about 95 line zeolite and about 95 to 40 percent by weight of a silica-alumina cracking catalyst. 

2. The method of claim 1 wherein said hydroalkylation conditions include a reaction temperature within the range of about 110* to 450*F. and a hydrogen partial pressure of at least one atmosphere.
 3. The method of claim 1 wherein said hydroalkylation conditions include a reaction temperature within the range of about 300* to 400*F. and a hydrogen partial pressure within the range of about 100 to 500 pounds per square inch gauge.
 4. The method of claim 1 wherein said Group VIII metal is nickel.
 5. The method of claim 1 wherein said Group VIII metal is palladium.
 6. The method of claim 1 wherein said catalyst consists essentially of tungsten, said Group VIII metal and said acidic oxide support.
 7. A method of claim 1 wherein said crystalline zeolite is prepared by an alternative sequence of at least two ion exchanges and two calcinations.
 8. The method of claim 1 wherein said catalyst is calcined at a temperature within the range of about 800* to 1500*F.
 9. The method of claim 1 wherein said catalyst is calcined at a temperature within the range of about 1000* to 1200*F.
 10. The method of claim 1 wherein said catalyst is reduced at a temperature within the range of about 400* to 1200*F.
 11. The method of claim 1 wherein said catalyst is reduced at a temperature within the range Of about 500* to 1000*F.
 12. The method of claim 1 wherein said aromatic hydrocarbon charge is benzene.
 13. The method for the catalytic hydroalkylation of benzene which comprises contacting said benzene charge and hydrogen at hydroalkylating conditions with a calcined and reduced catalyst comprising nickel and an acidic oxide support consisting essentially of a substantially alkali metal-free mixture of about 5 to 60 percent by weight of a crystalline zeolite and about 95 to 40 percent by weight of a silica-alumina cracking catalyst.
 14. The method for the catalytic hydroalkylation of benzene which comprises contacting said benzene charge, at reaction temperature of about 110*F., and hydrogen at superatmospheric hydrogen partial pressure less than about 500 pounds per square inch gauge, with a calcined and reduced catalyst comprising a Group VIII metal selected from the group consisting of cobalt, nickel, and palladium and an acidic oxide support consisting essentially of a substantially alkali metal-free mixture of 5 to 60 percent by weight of a crystalline zeolite and about 95 to 40 percent by weight of a silica-alumina cracking catalyst. 